Renegotiating Disciplinary Fields in the Life Sciences Printed Edition of the Special Issue Published in Philosophies www.mdpi.com/journal/philosophies Alessandro Minelli Edited by Renegotiating Disciplinary Fields in the Life Sciences Renegotiating Disciplinary Fields in the Life Sciences Editor Alessandro Minelli MDPI • Basel • Beijing • Wuhan • Barcelona • Belgrade • Manchester • Tokyo • Cluj • Tianjin Editor Alessandro Minelli University of Padova Italy Editorial Office MDPI St. Alban-Anlage 66 4052 Basel, Switzerland This is a reprint of articles from the Special Issue published online in the open access journal Philosophies (ISSN 2409-9287) (available at: https://www.mdpi.com/journal/philosophies/special issues/renegotiating disciplinary fields in life sci). For citation purposes, cite each article independently as indicated on the article page online and as indicated below: LastName, A.A.; LastName, B.B.; LastName, C.C. Article Title. 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Contents About the Editor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . vii Preface to ”Renegotiating Disciplinary Fields in the Life Sciences” . . . . . . . . . . . . . . . . ix Alessandro Minelli Renegotiating Disciplinary Fields in the Life Sciences Reprinted from: Philosophies 2020 , 5 , 43, doi:10.3390/philosophies5040043 . . . . . . . . . . . . . 1 Alessandro Minelli Disciplinary Fields in the Life Sciences: Evolving Divides and Anchor Concepts Reprinted from: Philosophies 2020 , 5 , 34, doi:10.3390/philosophies5040034 . . . . . . . . . . . . . 5 Igor Y. Pavlinov Multiplicity of Research Programs in the Biological Systematics: A Case for Scientific Pluralism Reprinted from: Philosophies 2020 , 5 , 7, doi:10.3390/philosophies5020007 . . . . . . . . . . . . . . 21 Salvatore Ivan Amato EvoDevo: An Ongoing Revolution? Reprinted from: Philosophies 2020 , 5 , 35, doi:10.3390/philosophies5040035 . . . . . . . . . . . . . 53 Rolf Rutishauser EvoDevo: Past and Future of Continuum and Process Plant Morphology Reprinted from: Philosophies 2020 , 5 , 41, doi:10.3390/philosophies5040041 . . . . . . . . . . . . . 75 Chris Fields and Michael Levin How Do Living Systems Create Meaning? Reprinted from: Philosophies 2020 , 5 , 36, doi:10.3390/philosophies5040036 . . . . . . . . . . . . . 113 v About the Editor Alessandro Minelli (Full Professor of Zoology at the University of Padova until retirement in 2011) served as Vice-President of the European Society for Evolutionary Biology. For several years, his research focus was biological systematics, but since the mid-1990s, his research interests have turned towards evolutionary developmental biology and the philosophy of biology. He is the author of ‘Biological Systematics’ (1993), ‘The Development of Animal Form’ (2003), ‘Forms of Becoming’ (2009), ‘Perspectives in Animal Phylogeny and Evolution’ (2009) and ‘Plant Evolutionary Developmental Biology’ (2018). vii Preface to ”Renegotiating Disciplinary Fields in the Life Sciences” Recent and ongoing debates in biology and the philosophy of biology reveal a widespread dissatisfaction with traditional explanatory frameworks. This is, for instance, the case of Neo-Darwinism, as it has been frequently advocated that evolutionary biology should replace the traditional gene-centered perspective with an organism-centered extended evolutionary synthesis, to account, e.g., for inclusive inheritance extending beyond genes and for phenotypic variation resulting from nonrandom mutation or biased by developmental processes. There are also problems with the current definitions or circumscriptions, often vague or controversial, of key concepts such as gene, species, and homology, and even of whole disciplinary fields within the life sciences, like developmental biology. To some extent, growing awareness of these conceptual issues and the contrasting views defended in their regard can be construed as marks of healthy debates in the field; however, this is also arguably a symptom of the need to revisit traditional, unchallenged partitions between the specialist disciplines within the life sciences. In the diversity of topics addressed and approaches to move beyond the current disciplinary organization, this Special Issue will hopefully stimulate further exploration towards an improved articulation of life sciences at the service of both science and philosophy. Alessandro Minelli Editor ix philosophies Editorial Renegotiating Disciplinary Fields in the Life Sciences Alessandro Minelli Department of Biology, University of Padova, Via Ugo Bassi 58B, I35131 Padova, Italy; alessandro.minelli@unipd.it; Tel.: + 39-389-949-4954 Received: 9 September 2020; Accepted: 3 December 2020; Published: 7 December 2020 The general problem around which this Special Issue revolves is that the way in which science is organized into specialties can have negative consequences on the progress of knowledge. Specifically, research priorities in biology and the circumscription of core concepts, both in biology and in the philosophy of biology, are very sensitive to the articulation of the Life Sciences in specialties. The problems deriving from an inadequately critical attitude towards this issue a ff ect biology as a whole due to the widespread lack of critical attitude, both in defending traditional disciplinary areas and in promoting new, or newly characterized and newly named, areas of research, often with an aggressive strategy. In a well-documented and incisive article entitled ‘Inclusion and Exclusion in the History of Developmental Biology’, Nick Hopwood [ 1 ] demonstrates how the articulation of a science in specialties impinges on decisions on what the important problems are and how these must be addressed. This conditioning has a social dimension, as the division of a science into specialized disciplines very strongly a ff ects the identity of a scientific community, and consequently the strategies of academic a ffi rmation, and the criteria for the allocation of funds and the organization of undergraduate degree programs (see also [2,3]). As soon as we become aware of the issue, action becomes possible. To use Hopwood’s words [ 1 ] (p. 1), ‘Disciplines are made, not found.’ Quite a few disciplines, indeed, are simply defined on the basis of inclusion or exclusion criteria. This is more frequent in the case of ancient disciplines and those of an applied nature, e.g., in the domains of medicine and agriculture. There is nothing to blame, from an operational point of view, if individual researchers or institutions (including scientific societies and their journals) address sets of biological phenomena that only have in common the fact of dealing with the diseases of humans or domestic animals (human or veterinary pathology), or with crop plants, or aquatic animals relevant to fisheries. A very di ff erent thing, however, is to consider these disciplines as areas suitable for the development of general concepts, or theories, with regard to the living. In the course of time, new disciplines emerge, generally characterized by a distinct set of problems or by a common technique, but often energetically pursuing less scientific targets such as the personal a ffi rmation of a scholar or the creation of a new lobby aiming at success in the competition for funding and academic positions [ 1 , 4 , 5 ]. This must be seriously addressed if we wish to identify an organization of the biological disciplines that is able to stimulate and support the conceptual refreshment of the sciences. To date, insu ffi cient attention has been paid to the new perspectives that show up every time the boundaries between two or more disciplines are questioned or newly determined, often facilitating, in this way, the emergence of new questions, new research directions, and, in any case, helping to refresh notions and terms, including general and fundamental ones, which interest the philosopher no less than the biologist, such as individual, generation, development, reproduction, and evolution. A collective e ff ort is needed to move forward in this direction, which I hope the essays forming this Special Issue will contribute to. None of us are claiming to write a new biology, or a new philosophy of biology. Our pages, however, express an e ff ort towards a vision of the living world that is both integrated and flexible in the identification of problems, concepts and their mutual relations. Philosophies 2020 , 5 , 43; doi:10.3390 / philosophies5040043 www.mdpi.com / journal / philosophies 1 Philosophies 2020 , 5 , 43 Inevitably, it is di ffi cult for each of us to avoid privileging the biological discipline to which we have devoted a lifetime of research. Even a scholar of the stature of Ernst Mayr, one of the most prestigious figures in evolutionary biology of the last century, insisted that there could not be a biology as a unitary science before the acceptance of an evolutionary vision of the living [ 6 ]—a questionable statement that neglects the importance of the cellular theory, as formulated by Schwann [ 7 ] ca. 20 years before the Origin [ 8 ]: ‘it may be asserted, that there is one universal principle of development for the elementary parts of organisms, however di ff erent, and that this principle is the formation of cells . [ . . . ] The development of the proposition, that there exists one general principle for the formation of all organic productions, and that this principle is the formation of cells, as well as the conclusions which may be drawn from this proposition, may be comprised under the term cell-theory.’ ([ 9 ]; pp. 165–166; italics as in the original). The insistence on the role of evolutionary theory as a unifying principle of biology also overshadows another great merit of Charles Darwin, naturalist extraordinaire, who developed his works, including the Origin , on a documentary basis, without taxonomic restrictions. This Species Issue includes five contributions. In their diversity, both the topics addressed and the approaches adopted to address them, these articles will hopefully stimulate further exploration towards an improved articulation of the Life Sciences at the service of both science and philosophy. My main intended message in ‘Disciplinary Fields in the Life Sciences: Evolving Divides and Anchor Concepts’ is that advances in both biology and the philosophy of biology will benefit from a degree of flexibility in the way in which problems’ agendas [ 10 ] are organized around (and through) concepts: this may require adopting unconventional perspectives and arguably, as suggested by other articles in this collection, a degree of pluralism too. Indeed, Igor Pavlinov defends in his essay, a ‘Multiplicity of Research Programs in the Biological Systematics: A Case for Scientific Pluralism’. Moving from a general philosophical position dominated by ideas of contemporary conceptualism and evolutionary epistemology, Pavlinov defends taxonomic pluralism. Biological diversity explored by biological systematics is a complex yet organized natural phenomenon that can be partitioned into several aspects, defined naturally with reference to various causal factors. These aspects are studied by research programs based on specific taxonomic theories. According to Pavlinov, each taxonomic theory is characterized by a unique combination of interrelated ontological and epistemological premises, which are most adequate to address one aspect of biological diversity. Phenetic, rational, numerical, typological, biosystematic, biomorphic, phylogenetic, and evo-devo research programs in systematics are recognized. From a scientific pluralism perspective, all of these research programs are of the same scientific significance, as possible parts of a generalized faceted classification. The main message of Chris Fields and Michael Levin’s paper titled ‘How Do Living Systems Create Meaning?’ is that the fundamental goal of Life Sciences is to understand how living systems create meaning. The authors discuss this question at multiple scales, from molecular interaction networks to the biosphere. Their focus is on identifying and understanding the roles of the reference frames that systems use, at each scale, to interpret their inputs. This involves understanding attention, memory, and the representation of self at multiple scales. From the perspective of disciplinary boundaries, Fields and Levin try to dissolve the one between biology and cognitive science. In ‘Evo-Devo: An Ongoing Revolution?’, Salvatore Ivan Amato discusses the epistemological status of Evo-Devo as a theory. Evo-Devo has been considered as a new paradigm, a new research program or a revolutionary science within biology, but the variety of stances within this field makes it di ffi cult to establish whether we are facing a new evolutionary synthesis. What is desirable is an adequate problematization of development, which can help clarify the relationship with both evolution and inheritance and take it one step further in the search for the identity of Evo-Devo. Rolf Rutishauser revises ‘The Past and Future of Continuum Plant Morphology’ from a process-thinking perspective that allows to perceive and interpret growing plants as developmental continua, as process combinations rather than as assemblages of structural units (“organs”) such as roots, stems, leaves, and flowers. This philosophical perspective was already favored by Agnes Arber 2 Philosophies 2020 , 5 , 43 (e.g., in her book on The Natural Philosophy of Plant Form [ 11 ]), and by Rolf Sattler, who first proposed his continuum approach in plant morphology exactly 50 years ago. This dynamic approach, known as continuum plant morphology, allows developmental geneticists and evolutionary biologists to move towards a more holistic understanding of multicellular plants in time and space. Funding: This research received no external funding. Acknowledgments: I express my gratitude to Philosophies , for o ff ering me the opportunity to edit this Special Issue, and to the authors of the four articles that follow in this collection. Conflicts of Interest: The author declares no conflict of interest. References 1. Hopwood, N. Inclusion and exclusion in the history of developmental biology. Development 2019 , 146 , dev175448. [CrossRef] [PubMed] 2. Maienschein, J. Shifting assumptions in American biology: Embryology, 1890–1910. J. Hist. Biol. 1988 , 14 , 89–113. [CrossRef] 3. Sapp, J. The struggle for authority in the field of heredity, 1900–1932: New perspectives on the rise of genetics. J. Hist. Biol. 1983 , 16 , 311–342. [CrossRef] [PubMed] 4. Sapp, J. Beyond the Gene. Cytoplasmic Inheritance and the Struggle for Authority in Genetics ; Oxford University Press: Oxford, UK, 1987; ISBN 0195042069. 5. Bowler, P.J. The Non-Darwinian Revolution. Reinterpreting a Historical Myth ; John Hopkins University Press: Baltimore, MD, USA, 1988; ISBN 0801843677. 6. Mayr, E. The Growth of Biological Thought. Diversity, Evolution and Inheritance ; Belknap Press of Harvard University Press: Cambridge, MA, USA, 1982; ISBN 0674364457. 7. Schwann, T. Mikroskopische Untersuchungen über die Uebereinstimmung in der Struktur und dem Wachsthum der Thiere und Pflanzen ; Sander’sche Buchhandlung (G.E. Reimer): Berlin, Germany, 1839. 8. Darwin, C. On the Origin of Species by Means of Natural Selection, or the Preservation of Favored Races in the Struggle for Life ; John Murray: London, UK, 1859. 9. Schwann, T. Microscopical Researches into the Accordance in the Structure and Growth of Animals and Plants ; Smith, H., Translator; Seydenham Society: London, UK, 1847. 10. Love, A.C. Explaining evolutionary innovations and novelties: Criteria of explanatory adequacy and epistemological prerequisites. Philos. Sci. 2008 , 75 , 874–886. [CrossRef] 11. Arber, A. The Natural Philosophy of Plant Form ; Cambridge University Press: Cambridge, UK, 1950. Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional a ffi liations. © 2020 by the author. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (http: // creativecommons.org / licenses / by / 4.0 / ). 3 philosophies Review Disciplinary Fields in the Life Sciences: Evolving Divides and Anchor Concepts Alessandro Minelli Department of Biology, University of Padova, I 35131 Padova, Italy; alessandro.minelli@unipd.it; Tel.: + 39-389-949-4954 Received: 10 October 2020; Accepted: 3 November 2020; Published: 4 November 2020 Abstract: Recent and ongoing debates in biology and in the philosophy of biology reveal widespread dissatisfaction with the current definitions or circumscriptions, which are often vague or controversial, of key concepts such as the gene, individual, species, and homology, and even of whole disciplinary fields within the life sciences. To some extent, the long growing awareness of these conceptual issues and the contrasting views defended in their regard can be construed as a symptom of the need to revisit traditional unchallenged partitions between the specialist disciplines within the life sciences. I argue here that the current relationships between anchor disciplines (e.g., developmental biology, evolutionary biology, biology of reproduction) and nomadic concepts wandering between them is worth being explored from a reciprocal perspective, by selecting suitable anchor concepts around which disciplinary fields can flexibly move. Three examples are o ff ered, focusing on generalized anchor concepts of generation (redefined in a way that suggests new perspectives on development and reproduction), organizational module (with a wide-ranging domain of application in comparative morphology, developmental biology, and evolutionary biology) and species as unit of representation of biological diversity (suggesting a taxonomic pluralism that must be managed with suitable adjustments of current nomenclature rules). Keywords: nomadic concept; nomadic discipline; anchor concept; anchor discipline; life cycle; generation; organizational module; species 1. Introduction The traditional articulation of biology into main research domains is not always satisfactory. For example, delimiting reproduction from other biological processes is not as easy as it might seem [ 1 ]. Let us focus on a strawberry plant. This produces runners that elongate horizontally on the ground, behaving like the branches of a growing plant, but after some time roots and leaves sprout on their lower face: a new plant takes shape, which ends up separating from the parent when the runner connecting them dries up. To use the terms introduced by John L. Harper and James White [ 2 ], even in the presence of a single genet (genetic individual), the production of runners leads to the formation of a new ramet , an anatomically separate individual, which therefore is the outcome of a reproductive event. Is this thus growth, or reproduction, or both? Another di ffi cult border separates developmental biology from some chapters of physiology, for example the physiology of nutrition or metabolism. In large snakes, e.g., pythons, in conditions of prolonged fasting the intestine undergoes a morphological and functional regression [ 3 ]; after a meal, cell proliferation reactivates the intestinal epithelium, which resumes its organization and functionality. This is accompanied by a rapid change in gene expression [ 4 ]. In terms of the mechanism, this is development; in terms of the function, this concerns the physiology of nutrition. Cellular metabolites can modulate the activity of epigenetic factors that establish functional links between nutrition and gene expression [ 5 , 6 ]. More generally, intricate connections between anabolic processes and developmental transitions have been discovered [7,8]. Philosophies 2020 , 5 , 34; doi:10.3390 / philosophies5040034 www.mdpi.com / journal / philosophies 5 Philosophies 2020 , 5 , 34 As discussed below, recent and ongoing debates in biology and in the philosophy of biology reveal widespread dissatisfaction with the current definitions or circumscriptions, often vague or controversial, of key concepts such as gene, individual, species, and homology, and even of whole disciplinary fields within the life sciences. To some extent, the long growing awareness of these conceptual issues and the contrasting views defended in their regard can be construed as a symptom of the need to revisit traditional, unchallenged partitions between the specialist disciplines within the life sciences. The problems deriving from an inadequately critical attitude towards the disciplinary partitions affect biology as a whole because of the unique diversity of the biological phenomena and the ubiquitous contrast between the inertial tendency to defend traditional disciplinary areas and a lively and often aggressive tendency to promote new or newly characterized and newly named research fields. The present paper is intended to contribute to a refreshment of this conceptual area. I articulate my argument as follows. In the next Section, I focus on concepts as units of scientific knowledge that “continuously undergo transformation, and [ . . . ] function by guiding ongoing scientific practice . A biology concept can motivate future scientific e ff orts, and it can also provide a sca ff old to direct the generation of new knowledge and the organization of complex knowledge.” [ 9 ] (p. 82, italics as in the original). I o ff er examples of concepts that change meaning according to the disciplinary context in which they are discussed and disciplined, including intentionally created ‘hybrids’ [10]. In Section 3, I suggest one of the possible strategies we could adopt in revising the disciplinary structure of biology. The current relationships between the traditional disciplines and a number of core concepts that change meaning while used in widely different disciplinary contexts is worth being explored from a reciprocal perspective, by selecting suitable anchor concepts around which disciplinary fields can flexibly move. Three tentative examples are offered. The first example suggests redefined concepts of generation as units in a periodization of the life cycles that opens new perspectives on both development and reproduction, and their evolution. The second example focuses on a notion of organizational module flexible enough as to be equally of use in comparative morphology, developmental biology and evolutionary biology, without the requirement for morphological, developmental and evolutionary modules to be overlapping or hierarchically nested. The third example suggests adopting a similarly flexible notion of species as unit of representation of biological diversity , as anchor species within which the different species notions can be accommodated in a disciplined form of pluralism. 2. Questionable Boundaries between Biological Disciplines 2.1. Multidisciplinary or Interdisciplinary? In biology, as in other sciences, interdisciplinarity has been steadily increasing in the last decades, but with a diversity of levels, intensity and outcome. The transfer of concepts, problems, and tools between disciplines is often strongly polarized, with the receiving discipline adopting them from a donating discipline [ 11 ], but often it is a two-way a ff air. In this case we can characterize the process as one of integration, either epistemic or organizational, or both [ 11 ]. Moreover, it is an accepted notion that in modern science many key concepts are shared by traditionally separate disciplines, and these are often concepts that do not lend themselves to precise definitions [12]. The biological concepts whose definition has proved more problematic and is still controversial are probably those of species, homology, gene, and individual. In the first case the controversy is particularly strong within the single biological discipline of systematics [ 13 ]; in the second case it involves di ff erent disciplines (morphology, phylogenetics etc.), mostly insofar as that these are united by the adoption of the comparative method [ 14 ]; see [ 15 ] for a broader perspective on these cases. The definition of gene has an overt transdisciplinary value, involving genetics in its various declinations, evolutionary biology, developmental biology, and the philosophy of biology [ 16 – 19 ]; the same applies for the definition of individual [20–25]. The need to address seriously, in a flexible and pluralistic way, the problem of a re-determination of the boundaries between biological disciplines is demonstrated by the number of concepts that 6 Philosophies 2020 , 5 , 34 in recent decades have assumed the value of nomadic concepts [ 26 , 27 ]. This term was proposed to describe concepts for which the meaning and domain of application changes with the new contexts into which they migrate. This has soon proved true also of the very notion of the nomadic concept [ 28 – 30 ]. I will use it to describe concepts that seems to be flexible enough to serve an epistemic role in di ff erent disciplinary contexts, but risk taking ever changing and not necessarily overlapping meanings. It is legitimate to think that the lack of shareable definitions for the terms listed in the penultimate paragraph is not only a consequence of progress in the disciplines in which each of them originated, but also evidence of the disputable delimitation of biological disciplines. Eventually, we must acknowledge the historical specificity of individual disciplines, and possibly also the historical specificity of our own concepts of discipline [31] (p. 51). 2.2. Hybrid Disciplines—The Case of Evolutionary Developmental Biology Gross conceptual rearrangements may be required by the emergence of a new hybrid discipline. This happened, in the last two decades of the 20th century, at the interface between evolutionary biology and developmental biology. Interestingly, these two disciplines had been diverging more and more during most of the century. In the mind of authoritative evolutionary biologists, development was a black box between genotype and phenotype whose content could be ignored [ 32 ]. On the other hand, the transition from the descriptive embryology of the 19th century (which had provided valuable contributions to the understanding of phylogenetic relationships) to the experimental embryology of the following century had seen a progressive loss of interest in the comparative aspects of developmental processes and a growing focus on experimental work restricted to a very small number of model species [ 33 , 34 ]. Eventually, however, formidable technical advances in the second half of the 20th century made it possible to implement a developmental genetics program. One of the most sensational results was the discovery of the involvement of homologous genes in the development of such di ff erent organisms as mouse and fruit fly. The increasingly accessible contents of the black box between genotype and phenotype proved to be of utmost interest not only for development biologists, but also for evolutionary biologists. The emergence of a new research field in this interface area is conventionally fixed by two books whose publication dates and titles respectively mark the completion of the maturation phase and the first full expression of the new discipline. In 1983, Rudy Ra ff and Thomas Kaufman published a book [ 35 ], the title of which ( Embryos, Genes, and Evolution ) clearly identified the subject, approach, and problems of this discipline, while Evolutionary Developmental Biology , the title of the book published nine years later by Brian K. Hall [ 36 ], provided the name (often abbreviated as evo-devo) by which the latter was definitively identified [37,38]. Gilbert and Burian’s early summary [ 39 ] that evo-devo “is both a synthesis between evolutionary biology and developmental biology and an ongoing negotiation between these two disciplines” (p. 61) is still up-to-date [ 40 ]. Winther [ 41 ] proposed to characterize evolutionary developmental biology as a trading zone , a catching term introduced by Galison [ 42 ] to indicate those interdisciplinary areas in which specific adoption and redefinition of both the concepts and the environment where they are implemented allow successful conceptual transfers [12,30]. For sure, conflicts cannot be avoided even in the best trading zones. In the case of evolutionary developmental biology, Love [ 43 ] has pointed to a hardly erasable tension between the two ‘souls’. Repeatability of experimental results requires the highest possible uniformity in the strains (often long inbred laboratory lines) used in the tests. But this choice potentially deletes all the intraspecific variation on which evolution is deemed to happen. In this tug of war between developmental biology and evolutionary biology, it is not surprising that studies e ff ectively coupling developmental genetics and population genetics (devgen-popgen [ 44 ]) are still few, despite a few excellent examples such as the already classic studies on the beaks of Darwin’s finches revisited from an evo-devo perspective [ 45 , 46 ]). 7 Philosophies 2020 , 5 , 34 2.3. Beyond Hierarchies and Facile Interdisciplinary Transfers In these years that witness so much talk about the need to broaden the traditional neo-Darwinian vision of evolution to move towards an extended synthesis [ 47 – 49 ] it is necessary, in my opinion, to make an even more generous and adventurous e ff ort and to seek, in an ever wider trading zone, to refresh the relationships between biological disciplines. An overarching question is the relationship between the disciplinary articulation of the natural sciences and a hierarchical vision of nature structured into levels of organization. The starting point of a debate that continues to this day [ 50 , 51 ], with an unceasing renewal of points of view and arguments, is a 1958 article by Oppenheim and Putnam [ 52 ] postulating both an articulation of nature in terms of levels of organization, and a close reciprocal correspondence between levels of organization in nature and the sciences that describe their components and develop theories on the relationships between them [ 53 ]. From these premises, Oppenheim and Putnam derived an entire reductionist program. A description of reality in terms of levels of organization seemed useful even to those who were ready to recognize that theories are not always “limited to single levels, that levels are always well defined, or that two or more entities can always be unambiguously ordered with respect to level” [ 54 ] (p. 215). But in more recent times, the progressive move away from the reductionist program of Oppenheim and Putnam was one of the reasons for the decreasing favor of the very notion of levels of organization [ 55 – 57 ], until its total rejection by some authors [ 58 ]. Others have brought their arguments against these dismissionary positions, while nevertheless proposing new interpretations (and new epistemic roles) for the notion of organizational levels. While rejecting an ontological interpretation according to which the world would be structured by levels of organization, Brooks and Eronen [ 59 ]; see also [ 60 , 61 ] nevertheless save this notion as useful in the abstract description of systems and as a guide in the search for new areas of investigation to be explored. On the other hand, DiFrisco [ 62 , 63 ] rejects the criteria thus far used in identifying organization levels, in terms of compositional relationships or spatial scale, and suggests a dynamic approach that recognizes levels defined on the basis of rates or time scales of processes. Baedke [ 64 ] challenges the general acceptance of a never changing existence of levels of organization such as cells, tissues, organs, and individual organisms and points to the necessity of addressing their dynamical nature over developmental time and in evolution. An overlooked consequence of the generalized acceptance of a vision of the living world in terms of compositional levels organized in part-whole relations [ 65 ] is the creation of disciplines through a copy-and-paste process. If in the study of humans and, more generally, of animals, it has proved useful to recognize a science of cells (cytology), a science of tissues (histology), a science of embryonic development (embryology) etc., this disciplinary articulation was accepted as sensible for all animals and even for multicellular organisms at large and corresponding disciplines were created for plants. Many biologists may take for granted, for example, the legitimacy of a plant embryology, but this should be resisted. In plant science, the use of the term embryo for the future seedling still enclosed within the seed casings was virtually unknown until 1788, when Gaertner [ 66 ] successfully introduced it in his treatise De fructibus et seminibus plantarum (On Plant Fruits and Seeds). Gaertner borrowed a number of terms and concepts from animal embryology. Some of these terms have remained in use for both plants and animals, but nobody would venture today to say, for example, that the placenta of plants is homologous to the placenta of mammals. Unfortunately, instead, the idea of an equivalence between what is called an embryo in either kingdom is still widespread, even among professionals [ 67 ]. 3. Moving Ahead—Nomadic Concepts or Nomadic Disciplines? I mentioned above that several core concepts of the life sciences have been taking continuously new meanings as long as their domain of application has been shifting from one biological discipline to another. Other adjustments to the meaning of concepts have accompanied the emergence of new subdisciplines within an older research area in which the concept was already in use, but with a 8 Philosophies 2020 , 5 , 34 di ff erent meaning. In a dialectic relationship between concepts and disciplines, the former have been continuing their nomadic existence, taking di ff erent meanings as a consequence of their changing association with disciplines, each of which acts as a semantic anchor context Traditionally, disciplines are taken for granted, as anchor disciplines , and concepts may nomadically wander from one to another. My suggestion here is, that a reversed relationship between disciplines and core concepts may prove useful, at least as an epistemic tool to be used to refresh the traditional divides separating a number of biological disciplines. I am suggesting indeed that we should perhaps move from a few anchor concepts around which nomadic disciplines may continuously evolve. In this reversed perspective, a suitably chosen concept becomes the anchor around which important problems agendas in a number of traditional disciplines can nomadically move. To be sure, within the general framework I am suggesting, one of disciplinary flexibility, no anchor concept shall be regarded as definitely fixed, but it may be worth exploring for a while its possible epistemic usefulness. I will o ff er here three examples. 3.1. Anchor Concept 1—Nomadic Disciplines in the Study of the Life Cycle Much of biology deals with objects, processes, and concepts about reproduction, development, or evolution. A great many problems have been successfully addressed by restricting attention to one or another of these main themes and often accepting—operationally at least—variously restrictive and partial notions of reproduction, development, or evolution. These partitions, however, limit the formulation of potentially interesting questions and thus constrain progress both in the life sciences and in the philosophy of biology. Therefore, it may be sensible to explore in a free, innovative way the notoriously di ffi cult and therefore challenging border areas between development and reproduction, and those between development and evolution. As mentioned above, the latter frontier came into the spotlight at the end of the last century and has been generally managed by making room for a new discipline, evolutionary developmental biology, within which new key concepts have emerged such as evolvability [ 68 , 69 ], modularity [ 70 ] and innovation [ 15 , 71 – 73 ]. However, a small number of scholars prefer a di ff erent path, suggesting a much closer integration between the two traditional disciplines [74,75]. The other boundary, the one between reproduction and development, may deserve a conceptual re-organization by treating these two chapters of biology as nomadic disciplines whose core problems vary according to their various association with a small number of anchor core concepts To the best of my knowledge, this reversal of perspective has not been formalized before; however, to see how this may operate, we can get advice from the literature. Let us start by comparing the complementary approaches of Paul E. Gri ffi ths, Karola Stotz, and James Griesemer to the relationships between reproduction and development. On the one hand, Gri ffi ths and Stotz take development as the core process, and reproduction as the linking one: “It is the developmental process that replicates itself across the generations” [ 76 ] (p. 227). A complementary proposal, centered instead on reproduction, comes from Griesemer, who takes reproducers as the units of multiplication, hereditary variation, and development: by reproduction, a parent generates an o ff spring that is able to develop so as to generate its own o ff spring [ 77 ]. Both perspectives have their merits and can suggest new, original research programs. In this context, it is fitting to remark that “Dobzhansky’s declaration (1973) [ 78 ] that nothing in biology makes sense except in the light of evolution notwithstanding, it is equally clear that evolution does not make sense except in the light of the rest of biology [ 79 ]. So, it is a toss-up which concepts must “come first” in order to understand “the rest”” [80] (p. 140). By introducing unprecedented perspectives on reproduction and development, these proposals contribute to the debates on the notion of the individual [ 22 – 27 ], the nature of development [ 81 – 83 ], and the diversity of hereditary mechanisms, which include Mendelian ones but are not limited to these [ 84 – 90 ]. These theoretical approaches put center stage the biological cycle , rather than the individual organism, both in ontogenetic and evolutionary perspectives [91–93]. 9